Laser interferometric studies of laser-induced surface heating and deformation

A Mach-Zehnder laser interferometer has been used to study the time-resolved deformation of metal and semiconductor surfaces caused by irradiation with the second harmonic of an Nd : YAG laser. The surfaces of thick and thin plates have been studied. The signals obtained for thick sample surfaces are compared to those derived from theory based on thermal expansion caused by heating of the surface by the laser pulse. For thin plates, mechanical vibrations due to induced thermal stress are observed and compared to theory.